A conventional single-phase ferroresonant voltage regulator normally comprises a combination of a nonlinear saturating inductor, a capacitor and a linear inductor in a series-parallel circuit arrangement. These components cooperate together to respond to an AC sinusoidal input voltage and provide a voltage regulated squarewave output voltage. The inductive magnetic components of a single-phase ferroresonant voltage regulator are normally combined in a single magnetic transformer structure which further provides input-output isolation and voltage transformation. The transformer structure usually combines the linear and saturating inductor in one magnetic structure by judicious use of magnetic shunts, which provide separate magnetic paths for primary and secondary leakage flux and permit the secondary magnetic flux path to saturate without the primary magnetic flux path saturating.
Typically when a three-phase ferroresonant voltage regulator circuit is desired, three single-phase ferroresonant magnetic structures are connected in a three- phase mode to obtain the desired three-phase ferroresonant regulator circuit. Sometimes in order to reduce the size of the combined magnetic components, the three saturated reactor portions of the ferroresonant structure and the three linear magnetic portions may each be individually merged into single three-phase structures. However, arrangements of this type as proposed, for example, in U.S. Pat. Nos. 3,205,430 and 3,379,961, still require two separate independent magnetic structures. This embodiment, in two separate structures, is necessary because the independent magnetic components are needed to achieve the separate primary and secondary magnetic flux paths in a three-phase ferroresonant regulator. There are instances where it is desirable to achieve a three-phase ferroresonant regulator in a single structure, expecially in situations where a reduction in space or weight is needed.